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A LiDAR Point Clouds Dataset of Ships in a Maritime Environment

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1681-1694页

作者： Qiuyu Zhang Lipeng Wang Hao Meng Wen Zhang Genghua Huang the College of Intelligent Systems Science and Engineering Harbin Engineering UniversityHarbin 150001China Key Laboratory of space Active Opto-Electronics technology Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China

For the first time, this article introduces a LiDAR Point Clouds Dataset of Ships composed of both collected and simulated data to address the scarcity of LiDAR data in maritime applications. The collected data are acquired using specialized maritime LiDAR sensors in both inland waterways and wide-open ocean environments. The simulated data is generated by placing a ship in the LiDAR coordinate system and scanning it with a redeveloped Blensor that emulates the operation of a LiDAR sensor equipped with various laser beams. Furthermore,we also render point clouds for foggy and rainy weather conditions. To describe a realistic shipping environment, a dynamic tail wave is modeled by iterating the wave elevation of each point in a time series. Finally, networks serving small objects are migrated to ship applications by feeding our dataset. The positive effect of simulated data is described in object detection experiments, and the negative impact of tail waves as no.se is verified in single-object tracking experiments. The Dataset is available at https://***/zqy411470859/ship_dataset.

关键词： 3D point clouds dataset dynamic tail wave fog simulation rainy simulation simulated data

Through-polymer,via technology-enabled,flexible,lightweight,and integrated devices for implantable neural probes

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Microsystems & Nano.ngineering 2024年第2期10卷 279-291页

作者： Cunkai Zhou Ye Tian Gen Li Yifei Ye Lusha Gao Jiazhi Li Ziwei Liu Haoyang Su Yunxiao Lu Meng Li Zhitao Zhou Xiaoling Wei Lunming Qin Tiger H.Tao Liuyang Sun College of Electronics and Information Engineering Shanghai University of Electric PowerShanghaiChina 2020 X-Lab Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghaiChina School of Graduate Study University of Chinese Academy of SciencesBeijingChina State Key Laboratory of Transducer technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghaiChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina School of Physical Science and technology ShanghaiTech UniversityShanghaiChina Center for Excellence in Brain Science and Intelligence technology Chinese Academy of SciencesShanghaiChina Neuroxess Co. Ltd.(Jiangxi)NanchangJiangxiChina Guangdong institute of Intelligence Science and technology HengqinZhuhaiGuangdongChina Tianqiao and Chrissy Chen institute for Translational Research ShanghaiChina

In implantable electrophysiological recording systems,the headstage typically comprises neural probes that interface with brain tissue and integrated circuit chips for signal *** advancements in MEMS and CMOS technology have significantly improved these components,their interconnection still relies on conventional printed circuit boards and sophisticated *** conventional approach adds considerable weight and volume to the package,especially for high channel count *** address this issue,we developed a through-polymer via(TPV)method inspired by the through-silicon via(TSV)technique in advanced three-dimensional *** inno.ation enables the vertical integration of flexible probes,amplifier chips,and PCBs,realizing a flexible,lightweight,and integrated device(FLID).The total weight of the FLIDis only 25%that of its conventional counterparts relying on adapters,which significantly increased the activity levels of animals wearing the FLIDs to nearly match the levels of control animals without ***,by incorporating a platinum-iridium alloy as the top layer material for electrical contact,the FLID realizes exceptional electrical performance,enabling in vivo measurements of both local field potentials and individual neuron action *** findings showcase the potential of FLIDs in scaling up implantable neural recording systems and mark a significant advancement in the field of neurotechnology.

关键词： alloy neural recording

Operational Characteristics of Loop Heat Pipe in Microgravity and no.mal Gravity Environments

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Journal of Thermal Science 2024年第4期33卷 1394-1408页

作者： ZHONG Siyuan XIE Rongjian LI Yunfei SUN Xiaojin shanghai Institution of technology and Physics Shanghai200083China University of Chinese academy of Sciences Beijing100049China shanghai institute of Satellite Engineering Shanghai200240China

The loop heat pipe(LHP)is an advanced,efficient two-phase heat transfer unit,whose operational performance may be affected by microgravity conditions in contrast to ground-based *** performance of on-orbit temperature data and ground test of a copper-propylene LHP with a condenser temperature range of 243.15 K to 303.15 K were employed to compared and *** LHP has successfully started up for more than 193 times with a good heat transfer performance and a stable start-up stabilization on-orbit under a complex orbital heating environment for more than eight *** a small heat load(10.0W),the average start-up time is 110.0 s while the start-up temperature ranges from 5.71 K-12.78 *** start-up time at large temperature differences in the high temperature zone will be higher than the time required for start-up at smaller temperature differences in the low *** the condenser temperature is 250.0 K,the stable temperature difference on orbit is 3.83 K,which is generally consistent in heat transfer compared to 2.20 K in the ground *** this paper,we can conclude that the on-orbit flight data up to no. can provide a reference to the design of subsequent LHP space applications.

关键词： Loop Heat Pipe(LHP) start up microgravity on-orbit experiment

High-precision X-ray polarimeter based on channel-cut crystals

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Nuclear Science and Techniques 2024年第3期35卷 30-39页

作者： Shang-Yu Si Zhong-Liang Li Wen-Hong Jia Lian Xue Hong-Xin Luo Jian-Cai Xu Bai-Fei Shen Lin-Gang Zhang Liang-Liang Ji Yu-Xin Leng Ren-Zhong Tai shanghai institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese academy of Sciences Beijing 100049China shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China shanghai institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800China

We report on using synthetic silicon for a high-precision X-ray polarimeter comprising a polarizer and an analyzer,each based on a mono.ithic channel-cut crystal used at multiple Brewster reflections with a Bragg angle very close to 45°.Experiments were performed at the BL09B bending magnet beamline of the shanghai Synchrotron Radiation Facility using a Si(800)crystal at an X-ray energy of 12.914 keV.A polarization purity of 8.4×10^(-9)was *** result is encouraging,as the measured polarization purity is the best-reported value for the bending magnet ***,this is the firstly systematic study on the hard X-ray polarimeter in China,which is crucial for exploring new physics,such as verifying vacuum birefringence.

关键词： X-ray polarimeter Vacuum birefringence Synchrotron radiation Channel-cut crystal

A seven-crystal spectrometer for high-energy resolution X-ray spectroscopy at shanghai Synchrotron Radiation Facility

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Nuclear Science and Techniques 2024年第9期35卷 82-91页

作者： Bing-Bao Mei Liang-Xin Wang Song-Qi Gu Xiao-Zhi Su Shuo Zhang Yao Wei Jing-Yuan Ma Zheng Jiang Fei Song shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201800China shanghai institute of Applied Physics Chinese Academy of SciencesShanghai 201204China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230026China

A Johann-type X-ray spectrometer was successfully developed at the hard X-ray branch(in-vacuum undulator with a 24-mm periodic length)of the energy material beamline(E-line)at the shanghai Synchrotron Radiation Facility(SSRF).This spectrometer was utilized to implement X-ray emission spectroscopy(XES),high-energy resolution fluorescence-detected X-ray absorption spectroscopy(HERFD-XAS),and resonant inelastic X-ray *** spherically bent crystals were positioned on the respective vertical 500-mm-diameter Rowland circles,adopting an area detector to increase the solid angle to 1.75%of 4πsr,facilitating the study of low-concentrate systems under complex reaction *** under the atmosphere pressure,the spectrometer covers the energy region from 3.5 to 18 keV,with the Bragg angle ranging from 73°to 86°during vertical *** offers a promised energy resolution of sub-eV(XES)and super-eV(HERFD-XAS).Generally,these comprehensive core-level spectroscopy methods based on hard X-rays at the E-line with an extremely high photon flux can meet the crucial requirements of a green energy ***,they provide substantial support for scientific advances in fundamental research.

关键词： X-ray emission spectroscopy High-energy-resolution X-ray spectrometer Johann geometry Energy materials SSRF

Decoupling of temporal/spatial broadening effects in Doppler wind LiDAR by 2D spectral analysis

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Chinese Physics B 2024年第3期33卷 447-452页

作者：刘珍张云鹏竹孝鹏刘继桥毕德仓陈卫标 space Laser Engineering Department Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Pulse echo accumulation is commonly employed in coherent Doppler wind LiDAR(light detection and ranging)under the assumption of steady ***,the measured spectral data are analyzed in the time dimension and frequency dimension to cope with the temporal wind shear and achieve the optimal accumulation time.A hardware-efficient algorithm combining the interpolation and cross-correlation is used to enhance the wind retrieval accuracy by reducing the frequency sampling interval and then reduce the spectral width calculation ***,the temporal broadening effect and spatial broadening effect are decoupled according to the strategy we developed.

关键词： Doppler wind LiDAR spectral analysis hardware efficiency spectrum broadening effects

Bunch-length measurement at a bunch-by-bunch rate based on time–frequency-domain joint analysis techniques and its application

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Nuclear Science and Techniques 2024年第4期35卷 165-175页

作者： Hong-Shuang Wang Xing Yang Yong-Bin Leng Yi-Mei Zhou Ji-Gang Wang shanghai institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese academy of Sciences Beijing 100049China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230026China shanghai Advanced Research institute Chinese Academy of SciencesShanghai 201204China

This paper presents a new technique for measuring the bunch length of a high-energy electron beam at a bunch-by-bunch rate in storage *** technique uses the time–frequency-domain joint analysis of the bunch signal to obtain bunch-by-bunch and turn-by-turn longitudinal parameters,such as bunch length and synchrono.s *** bunch signal is obtained using a button electrode with a bandwidth of several *** data acquisition device was a high-speed digital oscilloscope with a sampling rate of more than 10 GS/s,and the single-shot sampling data buffer covered thousands of *** bunch-length and synchrono.s phase information were extracted via offline calculations using Python *** calibration coefficient of the system was determined using a commercial streak ***,this technique was tested on two different storage rings and successfully captured various longitudinal transient processes during the harmonic cavity debugging process at the shanghai Synchrotron Radiation Facility(SSRF),and longitudinal instabilities were observed during the single-bunch accumulation process at Hefei Light Source(HLS).For Gaussian-distribution bunches,the uncertainty of the bunch phase obtained using this technique was better than 0.2 ps,and the bunch-length uncertainty was better than 1 *** dynamic range exceeded 10 *** technology is a powerful and versatile beam diagno.tic tool that can be conveniently deployed in high-energy electron storage rings.

关键词： Bunch-by-bunch diagno.tic Bunch-length measurement Synchrono.s phase measurement Joint time–frequency-domain analysis Longitudinal instability

Improving the spaceborne GNSS-R altimetric precision based on the no.el multilayer feedforward neural network weighted joint prediction model

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Defence technology（防务技术） 2024年第2期32卷 271-284页

作者： Yiwen Zhang Wei Zheng Zongqiang Liu Qian Xuesen Laboratory of space technology China Academy of Space TechnologyBeijing 100094China China academy of Aerospace Science and Inno.ation Beijing 100176China State Key Laboratory of space-Ground Integrated Information technology Beijing Institute of Satellite Information EngineeringBeijing 100194China

Global navigation satellite system-reflection(GNSS-R)sea surface altimetry based on satellite constellation platforms has become a new research direction and inevitable trend,which can meet the altimetric precision at the global scale required for underwater *** present,there are still research gaps for GNSS-R altimetry under this mode,and its altimetric capability canno. be specifically ***,GNSS-R satellite constellations that meet the global altimetry needs to be ***,the matching precision prediction model needs to be established to quantitatively predict the GNSS-R constellation altimetric ***,the GNSS-R constellations altimetric precision under different configuration parameters is calculated,and the mechanism of the influence of orbital altitude,orbital inclination,number of satellites and simulation period on the precision is analyzed,and a new multilayer feedforward neural network weighted joint prediction model is ***,the fit of the prediction model is verified and the performance capability of the model is tested by calculating the R2 value of the model as 0.9972 and the root mean square error(RMSE)as 0.0022,which indicates that the prediction capability of the model is ***,using the no.el multilayer feedforward neural network weighted joint prediction model,and considering the research results and realistic costs,it is proposed that when the constellation is set to an orbital altitude of 500 km,orbital inclination of 75and the number of satellites is 6,the altimetry precision can reach 0.0732 m within one year simulation period,which can meet the requirements of underwater navigation precision,and thus can provide a reference basis for subsequent research on spaceborne GNSS-R sea surface altimetry.

关键词： GNSS-R satellite constellations Sea surface altimetric precision Underwater navigation Multilayer feedforward neural network

An efficient schedulability analysis based on worst-case interference time for real-time systems

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Science China(Information Sciences) 2024年第9期67卷 88-104页

作者： Hongbiao LIU Mengfei YANG Lei QIAO Xi CHEN Jian GONG School of Computer Science and technology Xidian University China academy of space technology Beijing institute of Control Engineering

Real-time systems are widely implemented in the Internet of Things(IoT) and safety-critical systems, both of which have generated eno.mous social value. Aiming at the classic schedulability analysis problem in real-time systems, we proposed an exact Boolean analysis based on interference(EBAI) for schedulability analysis in real-time systems. EBAI is based on worst-case interference time(WCIT), which considers both the release jitter and blocking time of the task. We improved the efficiency of the three existing tests and provided a comprehensive summary of related research results in the field. Abundant experiments were conducted to compare EBAI with other related results. Our evaluation showed that in certain cases, the runtime gain achieved using our analysis method may exceed 73% compared to the stateof-the-art schedulability test. Furthermore, the benefits obtained from our tests grew with the number of tasks, reaching a level suitable for practical application. EBAI is oriented to the five-tuple real-time task model with stronger expression ability and possesses a low runtime overhead. These characteristics make it applicable in various real-time systems such as spacecraft, autono.ous vehicles, industrial robots, and traffic command systems.

关键词： five-tuple real-time task model real-time system spacecraft Internet of Things exact schedulability analysis worst-case interference time